College kids really appreciate a home cooked meal... so whatever you cook will be fine. I would keep some bagels & cream cheese, bananas, apples, make some muffins, pop tarts, juice & milk and such for breakfast...deli meat and cheese and bread for sandwiches, maybe make a huge bowl of pasta salad, once gone.. go with potato salad, for lunches, Lots of chips, crackers, dips, cut up veggies, hummus, guacamole, salsa. For dinners use your crock pot, chili and grilled cheese, shredded pork or chicken for tacos or other Mexican inspired dishes, homemade soup. This way you don't have to have a formal meals, just eat when your here and clean up after yourself.
Also washing clothes is a big thing, extra laundry detergent would be on my list. If they are driving maybe a couple of cheapo clothes baskets, to take the clean stuff back to school in.
I would tell your daughter and her friend what you expect as far as keeping up and helping in the kitchen with cleaning and trash, cleaning the bedrooms & bathrooms, and being respectful of coming in at all hours of the night. Just be up front and things will go smoother.
When my DD was in college and she and her friends were in and out thats how I did it.. Lots of grab and go items...